Automatic dishwashers can be severely damaged when exposed to low temperatures for a duration long enough to cause water to freeze. These appliances have standing water present at all times in the pump assembly which is usually mounted at the bottom of the tub. Domestic water is also present in the supply line, while rinse water remains in the low point of the drain hose. All of these parts are subject to mechanical damage due to the expansion of water during a freeze. The pump, which is usually integral to the motor and/or transmission, is a particularly expensive component of an automatic dishwasher. Beyond the expense to replace whichever component is damaged, a significant labor charge is incurred to have a service technician remove the appliance from the cabinet, disassemble it, and replace it. Collateral damage to the home is also avoided as a cracked pump or water line can flood the environment after a thaw.
There are many reasons why a dishwasher could be exposed to temperatures which would cause the residual water to freeze. This is a particular concern in northern climates during the winter months.
Kitchens are often difficult to heat, due to the lack of baseboard for heat radiators. The need for appliances and cabinets along the walls, plus the need for various doorways into the room, can limit the linear feet available for baseboard heat.
Exterior doors are often placed in or near the kitchen which can allow cold air from outdoors to enter the room. Older homes may have poor or no insulation allowing cold air to penetrate the space behind an automatic dishwasher.
An automatic dishwasher could be installed on an outside wall, between base cabinets and under a countertop, which limits its exposure to the heated room. A dishwasher could be placed on a northern wall, which has limited sun and tends to be cold.
A kitchen may have the room heat reduced by a set-back thermostat for up to 12 hours over night between the evening meal and breakfast. A kitchen is often non-occupied between these hours.
The dishwasher maybe installed in a vacation home, such as a ski lodge or cabin, with the heat set to a low temperature during periods of non-occupancy. The unit may be installed in a pantry, garage, or storage area with limited or no heat.
U.S. Pat. No. 7,837,127 relates to a ventilation system for exchanging the air in a room with outside air. The system comprises a fine wire heat exchanger having a first channel and a second channel, which channels are in heat exchanging contact with each other, and wherein the first channel has an inlet connected to outside air and an outlet connected to the air in the room, and wherein the second channel has an inlet connected to the air in the room and an outlet connected to the outside air, balancing means for balancing the flow in both channels, such that the heat transfer is maximized.
U.S. Pat. No. 5,560,060 relates to a system and method for adjusting the operating cycle of a cleaning appliance. A controller having a decision system receives turbidity and temperature measurements from turbidity and temperature sensors and uses these measurements to adjust the operating cycle of the machine to the level of soil of the articles to be washed, the rate of soil removal, and the temperature of the water used for washing.
U.S. Pat. No. 5,984,194 relates to a valve for use in machines for washing, such as laundry machines and dishwashers, that includes a hollow valve body wherein a current of water flows, entering the valve body via at least one inlet of the valve, and at least one plug element for allowing and preventing the outflow of water from a corresponding outlet of the valve. The valve is connected to at least one temperature sensor device having an open and closed condition of an electrical connection and in that the sensor device has a preset trigger temperature which, when reached, causes the change from a state of closure to one of opening of the connection or vice versa.
U.S. Pat. No. 6,625,850 relates to a dishwasher sanitation cycle that includes sampling a temperature of rinse water inside a dishwasher, executing a heating cycle to keep water temperature at optimal levels, and executing a heat sum cycle to ensure that dishes are sanitized according to accepted standards.
US patent publication 2011/0224834 relates to a method for identifying operating conditions of a domestic appliance, a temperature of an operating agent of the appliance or of a component detected by a temperature sensor. The ambient temperature is detected by the temperature sensor before the programming mode, in an initialization phase. At least one reference temperature value is defined that represent a critical value for the programming mode of the appliance. The programming mode is prevented from beginning as a function of the comparison of the measured ambient temperature with at least one reference temperature value. The programming mode is prevented from beginning until the ambient temperature has reached a value that is in an acceptable range in comparison with the reference temperature value.
US patent publication 2010/0126604 relates to a demand type, multiple use, hot water distribution and freeze protection system and method that responds to the user's desire for hot water at a particular sink or fixture by delivering hot water rapidly to that fixture only, without running water down the drain. The system requires only one pump at the water heater, and does not require a dedicated hot water return line, but works with a dedicated line in retrofit applications. Circulating water in the plumbing system can also be used to protect plumbing from freeze damage. Each valve and activation device operates by transmitting a start command to the valve controller which sends the pump controller a start signal, the valve to open, hot water to circulate and the valve to close when the hot water arrives at the fixture preventing heated water from filling the cold water line.